The invention relates to a mount part for commutator brushes of an electric motor.
The arrangement of commutator brushes for an electric motor is known. DE 101 12 427 A1 has disclosed an electromotive adjusting unit for a metering system of an internal combustion engine. In this case, the brush holder is in the form of a so-called hammer-type brush holder which has two electrically conducting leaf springs which each bear a commutator brush and protrude freely and which are, with one of their ends, injection-molded on a mount plate and are connected to electrical conductors leading to plug contacts of the plug. The leaf springs comprise rectangular sheet-metal strips. In the case of a motor vehicle, a stationary, constant, mechanical contact between the collector and the commutator brushes is of critical importance. In the arrangement of the commutator brushes in accordance with the prior art, one disadvantage is the fact that when mechanical disturbances are introduced into the system, which may be brought about by, for example, oscillations from the outside, it is very easily possible for the commutator brushes to be lifted off from the commutator. This results in a current interruption with brush sparking, high carbon wear owing to erosion, induced voltage peaks being produced and the instability of electrical control circuits.
DE 76 09 316 has disclosed a mount part of the type described initially. With this mount part, the trapezoidal region is completely reinforced such that it cannot contribute to the build-up of a bearing force.
GB 1 062 700 describes a brush holder which is clamped between outer and inner stops in the form of journals, whereas U.S. Pat. No. 4,596,941 describes clamping by means of a piercing contact. This document also describes latching of the brush mount in an elevated position. U.S. Pat. No. 5,734,219 describes a brush system having three resiliently bearing brushes.
The invention is therefore based on the object of providing a mount part for commutator brushes with which the commutator brushes are largely prevented from being lifted off from the commutator even when relatively significant mechanical disturbances are introduced.